Field of the Invention
The present invention relates to a packet routing bus in a communication system, and more particularly, to a loop test apparatus of a packet routing bus in a communication system and a loop test method thereof
2. Discussion of the Related Art
In a communication system, methods of data communication include a simplex communication mode and a duplex communication mode. These modes operate in accordance with the data flow transmission between two systems. The duplex transmission mode includes a half-duplex transmission mode and a full-duplex transmission mode.
Since the full-duplex transmission mode allows duplex transmission between two systems at the same time, free data flow can be achieved. In that regard, the full-duplex transmission mode is useful for transmitting and receiving a large amount of data.
A data packet (also referred to as “packet data” or “packet”) relates to a data bundle used in a data transmission. Packet data is commonly transmitted though a telephone or network. In a packet data transmission, data is not successively transmitted beginning to end. Rather, data to be transmitted is divided into appropriate sizes to form a data packet, and these packets are transmitted one by one. Each data packet includes a certain size of data, a destination address and control information, such as a control sign. For example, a data packet can be transmitted through a packet exchanger using header data and can exist in various sizes, such as 53 bytes or 1024 bytes, depending on the packet exchanger.
Routing relates to a process for determining the appropriate path for transmitting data in a communication network. A router commonly determines where to send data and transmits data to the destination system.
A base station system according to a related art will be explained with reference to the attached drawings. FIG. 1 is a block diagram showing transmitting and receiving nodes in a network board which enables inter processor communication (IPC).
As shown in FIG. 1, the transmitting and receiving nodes in a network board 100 includes first to fourth receiving nodes 11, 12, 13 and 14 (Rx nodes), first to fourth transmitting nodes 16, 17, 18 and 19 (Tx nodes), transmitting and receiving packet routing buses 20 and 21 of a full-duplex transmission mode, a transmitting bus master 22, a receiving bus master 23, and a U-turn node 15. The receiving nodes 11-14 are connected to a trunk node of a base station controller. The transmitting nodes 16-19 are connected to a processor board in the base station system (for example, an alarm collection and maintenance board assembly) and a system clock board (for example, a timing management circuit board assembly). During operation, the transmitting bus master 22 searches the receiving nodes 11-14 and generates a control signal (a “read” signal) if there is a data packet in the receiving nodes 11-14. If the control signal is triggered, the data packet is read into the transmitting packet routing bus 20 and written to a destination transmitting node of the transmitting nodes 16-19. The receiving bus master 23 searches the transmitting nodes 16-19 and generates a control signal if there is a data packet in the transmitting nodes 16-19. If the control signal is triggered, the data packet is read onto the receiving packet routing bus 21 and written to a destination receiving node of the receiving nodes 11-14. The U-turn node 15 U-turns the data packet generated by the transmitting nodes 16-19 if the destination address of the data packet generated by the transmitting nodes 16-19 uses the transmitting nodes 16-19 as the destination.
The transmitting nodes 16-19 are matched with the receiving packet routing bus 21, so that the data packet of the transmitting nodes 16-19 are read onto the receiving packet routing bus 21 and are written to the receiving nodes 11-14 and the U-turn node 15.
The receiving nodes 11-14 and the U-turn node 15 are matched with the transmitting packet routing bus 20, so that the data packet from the receiving nodes 11-14 and the U-turn node 15 are read onto the transmitting packet routing bus 22. The transmitting nodes 16-19 are also matched with the transmitting packet routing bus 20, so that the data packet of the no transmitting packet routing bus 20 is written to the transmitting nodes 16-19.
FIG. 2 is a flow chart showing a packet routing method for transmitting and receiving nodes in the related art. The packet routing method used by the transmitting and receiving nodes 11-14, 16-19 in the network board 100 of FIG. 1 will be described.
As shown in FIG. 1, the receiving bus master 23 searches for the presence of the transmitting data packet in the transmitting nodes 16-19 matched with the receiving packet routing bus 21 (step S1).
If the transmitting data packet is found in the transmitting nodes 1619, the receiving bus master 23 generates a control signal which causes the data packet of the transmitting nodes 16-19 to be read onto the receiving packet routing bus 21 (step S2).
Then, the receiving bus master 23 determines the destination node of the data packet by searching for the destination address data from the data packet and writes the data packet in the destination node of the receiving packet routing bus 21 (step S3). At this time, one of the receiving nodes 11-14 is the destination node and the data packet is written to one of the receiving nodes 11-14.
The data packet is then routed from the receiving nodes 11-14 to a trunk node of the base station controller (BSC). However, if one of the transmitting nodes 16-19 is the destination node, the data packet is written to the U-turn node 15.
The transmitting bus master 22 determines whether or not there is a data packet in the receiving nodes 11-14 and the U-turn node 15 matched with the transmitting packet routing bus 20 (step S4).
As a result, if there is data packet in the receiving nodes 11-14, the transmitting bus master 22 generates a control signal which causes the data packet of the receiving nodes 11-14 to 15 be read onto the transmitting packet routing bus 20. The transmitting bus master 22 then searches for destination address data from the data packet read on the transmitting packet routing bus 20.
If there is address data in the data packet, the destination node of the data packet is determined and the data packet is written to the destination node (one of the transmitting nodes 16-19). The data packet is then routed from one of the transmitting nodes 16-19 to another processor board in the base station system.
Also, if there is a data packet in the U-turn node 15, the transmitting bus master 22 transfers the data packet from the U-turn node 15 to the transmitting data packet bus 20 with the use of a control signal. The transmitting bus master 22 searches for destination address data from the read data packet to determine a destination transmitting node. If the data packet is written to the destination transmitting node, the data packet is routed from the destination transmitting node to another processor board of the base station (step S5).
The U-turn node 15 is used in case where the transmitting nodes 16-19 route the data packet to the other processor board of the base station system connected to the transmitting nodes 16-19. The presence of a data packet in the transmitting nodes 16-19 is searched for by the receiving bus master 23. If there is a data packet in the transmitting nodes 16-19, the data packet is read into the receiving packet routing bus 21.
Subsequently, if the destination address of the data packet read in the receiving packet routing bus 21 is the other processor board of the base station, the receiving bus master 23 writes the data packet to one of the transmitting nodes 16-19. At this time, since the data packet cannot be directly written from the receiving packet routing bus 21 to the transmitting packet routing bus 20, the data packet is written to the U-turn node 15. Then, the transmitting bus master 22 reads the data packet from the U-turn node 15 and determines the destination address from the data packet. The data packet is then written to the transmitting node (one of the transmitting nodes 16-19) with the appropriate destination address.
FIG. 3 is a detailed view showing the transmitting and receiving nodes of FIG. 1. In FIG. 3, the first receiving node 11 is representative of the receiving nodes 11-14 in FIG. 1 and the first transmitting node 16 is representative of the transmitting nodes 16-19 in FIG. 1.
The first receiving node II includes a transmitting driver 11a and a receiving driver 11b. The transmitting driver 11aroutes the data packet written in the receiving packet routing bus 21 to the trunk node of the base station controller. The receiving driver 11b reads the data packet routed from the trunk node of the base station controller to the transmitting packet routing bus 20.
The first transmitting node 16 includes a transmitting driver 16a and a receiving driver 16b. The transmitting driver 16a routes the data packet written in the transmitting packet routing bus 20 to the other processor of the base station system. The receiving driver 16b reads the data packet routed from the other processor of the base station system to the receiving packet routing bus 21.
In a network which enables communication between the processors of the base station in the related art communication system, in order to identify whether the data packet is normally routed in both the transmitting node matched with the receiving packet routing bus and the receiving node matched with transmitting packet routing bus, it is necessary to identify whether (1) the processor board of the base station connected with the transmitting node has received the data packet routed in the receiving node and (2) the trunk board of the base station controller connected with the receiving node has received the data packet routed in the transmitting node. Accordingly, to identify transmission and reception of the data packet, a communication system such as the base station and the base station controller should be established. Finally, the related art communication system has a further problem in that functions of the respective transmitting and receiving nodes cannot be identified independently before the base station and the base station controller are established.